Dutch Prince Johan Friso is in a critical condition in hospital after being buried in an avalanche while skiing off a ski trail in the Austrian Alps, authorities say.

Queen Beatrix's middle son was pulled unconscious from the snow 20 minutes after the accident on Friday and resuscitated, the mayor of the upscale western resort of Lech told the Austria Press Agency (APA).

The Prince was skiing with one companion away from marked ski runs when the mass of snow, 30 metres wide and 40 metres long, hit them around midday, APA said.

The 43-year-old prince, who gave up his right to the throne a decade ago, was flown to the university clinic in the western city of Innsbruck.

His condition was "stable but life-threatening", and the Queen and his wife were at his side, the Dutch government said in a statement.

The Dutch royal family often spends winter holidays in Lech in the province of Vorarlberg - which like other parts of Austria has been blanketed with heavy snow in recent weeks.

Many parts of the country have avalanche alerts in effect, but some adventurous skiers still venture off ski trails. In Lech, the alert level was four on a scale of five at the time.

"It was in open space, not on a secured piste (ski trail)," a Lech police official said about the place where the accident took place.

A second Dutch government statement suggested it could take days before doctors would have a clearer picture of the Prince's medical prognosis.

"The rescue chain functioned perfectly and worked within a short time," the police official in Lech said.

"After the emergency call, rescue crews were on the scene with rescue helicopters. He could be located immediately and freed," he said, adding the Prince had been skiing with a group.

A tourism official in Lech told APA the Prince was wearing a beeper that helped rescue crews find him quickly and that the companion was able to free himself and call for help.

Johan Friso gave up his right to the Dutch throne when he married a commoner whose past was considered too tainted for her to become a member of the Dutch royal house.

When he asked for official permission in 2003 to marry Mabel Wisse Smit, Dutch media published details of her relationship with mobster Klaas Bruinsma, who was shot and killed in 1991 in front of the Amsterdam Hilton hotel.

Following the revelations, the couple decided not to get official permission for their marriage.